1. Field of the Invention
The present description generally relates to aircraft, and particularly to securing doors in aircraft.
2. Description of the Related Art
There is a compelling desire to improve security in aircraft. One area of particular concern is the door in the bulkhead that separates the flightdeck and the passenger cabin of the aircraft. The door must allow access between the flightdeck and the cabin under certain circumstances, for example, when authorized flight crew requires access. The door must prevent access under other circumstances, for example, when unauthorized persons attempt to access the flightdeck. Existing systems include a switch that is controlled from the flight deck and which provides two options (i.e., door locked or latched, door unlocked or unlatched).
Existing doors are designed to give way under sudden decompression of either the cabin or the flightdeck, allowing the rapid equalization of the pressure between the flightdeck and the cabin. This is a desirable effect, which may prevent more substantial damage from occurring to the aircraft, caused by the significant variation in pressure between the flightdeck and the cabin during a rapid decompression event. One proposal for improving security includes equipping aircraft with stronger doors and latches in the bulkhead separating the flightdeck and the passenger cabin. However, the additional structural integrity will prevent the doors from giving way during sudden decompression event, preventing the desired rapid equalization of pressure throughout the aircraft.
Thus, there is a need for an improved approach in aircraft design that allows for structurally secure doors, while also permitting fast pressure equalization during rapid decompression events. Further, there is a need for an improved approach to controlling access through doors in the bulkheads in aircraft.
In one aspect, a system for monitoring interior pressure change in an aircraft having a bulkhead separating a flight deck portion of the aircraft from a cabin portion of the aircraft, the bulkhead including a door and a latch, includes a first pressure sensor that provides flight deck pressure signals corresponding to a rate of change of an ambient pressure in the flight deck portion of the aircraft; and a first comparator responsive to the flight deck pressure signals to provide a first actuation signal in response to a comparison of the rate of change of the ambient pressure in the flight deck portion to at least a first minimum reference level. Determining the rate of pressure change may permit a quicker reaction to a rapid decompression event than would be possible based on a determination of the difference in pressures across a bulkhead.
In another aspect, a system for monitoring interior pressure change for an aircraft includes a first pressure sensor responsive to a rate of change of a first ambient pressure in a first portion of the aircraft to produce an output proportional to the rate of change of the first ambient pressure in the first portion of the aircraft; and a comparator responsive to the output of the first pressure sensor to control a door locking mechanism based on a comparison of the rate of change of the first ambient pressure to at least a first reference level.
In yet another aspect, a method of monitoring interior pressure change in an aircraft having a bulkhead separating a flight deck portion of the aircraft from a cabin portion of the aircraft, the bulkhead including a door and a latch includes determining a rate of change in an ambient pressure in the fight deck portion of the aircraft, and automatically unlatching the door if the rate of change in the ambient pressure in the flight deck portion of the aircraft exceeds a first minimum threshold.
In even a further aspect, a method of monitoring interior pressure change in an aircraft having a bulkhead separating a flight deck portion of the aircraft from a cabin portion of the aircraft, the bulkhead including a door and a latch includes repeatedly determining the ambient pressure in the flight deck portion of the aircraft; and differentiating the determined ambient pressure in the flight deck portion with respect to time.
In yet a further aspect, a method of monitoring interior pressure change in an aircraft having a bulkhead separating a flight deck portion of the aircraft from a cabin portion of the aircraft, the bulkhead including a door having a latch determining a rate of change in an ambient pressure in the fight deck portion of the aircraft; automatically unlatching the door if the determined rate of change in the ambient pressure in the flight deck portion of the aircraft is between a first minimum threshold and a first maximum threshold, the first maximum threshold greater than the first minimum threshold.
In even another aspect, a method of operating a latch of a door in an aircraft includes determining whether the rate of change in the first interior pressure of the first portion of an aircraft satisfies a defined first set of criteria; and providing an unlatching signal to an actuator to unlatch the door if the rate of change in the first interior pressure in the first portion of the aircraft meets the defined first set of criteria.
In still a further aspect, pressure rate sensitive system for use in an aircraft having a flight deck and a cabin separated from the flight deck, includes first rate of change means for determining a rate of change in a pressure in the flight deck; first determination means for determining whether the rate of change in the pressure in the flight deck satisfies a defined first set of criteria; and access controlling means responsive to the first determination means for controlling access between the flight deck and the passenger cabin of the aircraft.